国家自然科学基金项目31271627;周口师范学院高层次人才科研启动经费ZKNU2015109;国家公益性行业农业科研专项201203077资助。 This study was supported by the National Natural Science Foundation of China31271627;the Start-up Fund for High-level Scholars of Zhoukou Normal UniversityZKNU2015109;the China Special Fund for Agro-Scientific Research in the Public Interest201203077